Low cost convergence apparatus with cathode ray tube neck tolerance accommodation

ABSTRACT

In a cathode ray tube convergence apparatus, a plurality of housing units are circumferentially spaced about the neck of the cathode ray tube to form legs individually aligned with each of a plurality of electron guns corresponding to each of three colors of a color television receiver. Each of the housing units is connected to another of the housing units by connective members at the ends of a neck engaging portion including two radially spaced and tangentially extending surfaces which mate with similar surfaces on other housings to allow radial displacement of each of the housing units. Each of the pairs of radially spaced surfaces include radially projecting stop members associated therewith which provide limits on the radial displacement of the housing units with respect to the neck. A flexible annular clamp with radial guideways engages each housing unit and limits displacement to the radial direction.

m at f i A 31 @4311.) 1 sRufSYREEEfiWE; 21: s CH R00 *Ci Q Uite States Patent 1 11 1 3,800,255 Highland Mar. 26, 1974 LOW COST CONVERGENCE APPARATUS Primary Examiner-George Harris WITH CATHODE RAY TUBE NECK TOLERANCE ACCOMMODATlON 57] ABSTRACT [75 Inventor: Andrew Highland Chesapeake In a cathode ray tube convergence apparatus, a plural- [73] Assignee: General Electric Company, ity of housing units are circumferentially spaced about Port mouth, V the neck of the cathode ray tube to form legs individuv ally aligned with each of a plurality of electron guns [22] Flled: July 1968 corresponding to each of three colors of a color televi- [21] A N 777,929 sion receiver. Each of the housing units is connected to another of the housing units by connective members at the ends of a neck engaging portion including [52] US. Cl. .1 335/212, 313/77 two radially Spaced and tangentially extending Sub [5 [13t- Cl. r faces mat'e Similar surfaces on other hous Field of Search i g to allow radial displacement of each of the h ing units. Each of the pairs of radially spaced surfaces [56] References and include radially projecting stop members associated UNITED STATES PATENTS therewith which provide limits on the radial displace- 3,500,270 3/1970 Anthony 335/212 ment of the housing units with respect to the neck. A 3,165,677 1/1965 Gostyn et a1 335/212 flexible annular clamp with radial guideways engages 3,179,857 5 m rman 313/77 X each housing unit and limits displacement to the radial 3,303,444 2/1967 Leeb et al r r. 335/212 direction 3,349,268 l0/l967 Babcock et al. 335/212 X 14 Claims, 7 Drawing Figures PATENIEnm m m4 3,800,255

sum 1 or 2 FEM?" INVENTOR. ANDREW HIGHLAND J'R.

ATTORNEY LOW COST QONVERGENCE AFPARATUS WITH CATHODE RAY TUBE NECK TOLERANCE ACCOMMODATION BACKGROUND or THE INVENTION The present invention relates to an apparatus for controlling the electron beams of cathode ray tubes, and more specifically, to an apparatus for controlling convergence of the various electron beams in a color cathode ray tube.

It is necessary in certain forms of color cathode ray tubes of the multibeam type to effect convergence of the various electron beams at appropriate points on an aperture mask. In this regard, magnetic core members have been commonly employed to achieve static convergence of the various beams while windings are positioned on the core members to provide dynamic convergence. However, the overall structure including the housing for the static and dynamic convergence units has generally been quite complex where any effort was made to provide a means of accommodating any tolerances in the neck of the cathode ray tube while maintaining accuracy in alignment and serviceability.

In particular, there has always been and still is a need to provide a means of increasing the cylindrical aperture of a convergence apparatus which receives the cathode ray tube neck. Generally, this need has-been satisfied by using a number of separable parts on the convergence housing which were utilized to connect each of a plurality of separable housing units individu- 1 ally aligned with the electron guns of the cathode ray tube. While these separable parts did provide the necessary means of accommodation for cathode ray tube neck tolerances with some degree of serviceability, there were at least two problems created.

First, the separable parts performed only a connective function and did not lend themselves to the maintenance of a rather definite and predetermined relationship of each of the housing units with respect to the other and the electron guns of the cathode ray tube. Thus, while the prior art convergence housings could provide accommodation for a variable cathode ray tube neck diameter, there were problems associated with the proper relationship between units of the housing and the electron guns to provide the precision in alignment necessitated by the high performance required of a color television receiver. Generally speaking, it is necessary to maintain a plus or minus five degree relationship between each of the housing units on the cathode ray tube neck to meet this standard of performance.

Second, the convergence housings of the prior art were expensive to manufacture by todays assembly line techniques due to the individual attention required of each convergence apparatus with its multiple separable parts. With this complication arising out of the separable parts associated with the connective means there came a further and more far reaching complication. Namely, separable parts at the connective means frequently necessitated the use of separable parts to retain the magnetic core members, magnets associated therewith, and pole shoes mounted between the cores and the neck of the cathode ray tube.

In summary, the prior art has been lacking in accuracy where an attempt has been made to accommodate tolerances in the diameter of the cathode ray tube neck and has been expensive to build because of the utilization of numerous separable parts used in order to provide the accommodation and retain the various elements of the apparatus. Yet, it is not desirable to so limit the separability of thevarious individual housing units surrounding the neck to the point of eliminating serviceability; i.e., the removal and the replacement of the individual housing units as repair might require.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a convergence apparatus which will accommodate the tolerances in the neck of the cathode ray tube.

It is another object of this invention to provide a convergence apparatus which can accommodate tolerances in the neck of the cathode ray tube and still retain the requisite accuracy in alignment with the electron guns of the cathode ray tube.

It is a further object to achieve the accommodation and alignment with a simplified unit at a reduced cost.

And it is a still further object to achieve the above while retaining the capability of removal and replacement of one of the plurality of housing units surrounding the neck of the cathode ray tube.

Briefly stated, and in accordance with one embodiment of the invention, there is provided a convergence apparatus for use with a cathode ray tube including a neck traversed by a plurality of electron beams, which apparatus comprises a plurality of housing units forming legs which are circumferentially disposed around the neck. Each of the housing units includes a neck engaging portion terminated with connective means engaging complementary or mating connective means of another of the housing units along two radially spaced and tangentially extending paths. An annular clamp with guideways engages each housing unit at the neck engaging portion and along parallel surfaces. The tangentially extending paths and guideways allow the housing units to be substantially radially displaced to accommodate the tolerances of the cathode ray tube neck while still maintaining the necessary alignment.

In the more detailed aspects of this embodiment of the invention, the tangentially extending paths are achieved by the provision of a pair of tangentially extending surfaces in each connective means and stop means associated with each pair which are designed to allow sufficient radial displacement of the individual housing units to accommodate the outer limit in cathode ray tube neck tolerances. The clamp includes radial slots to provide sufficient flexibility in order to accommodate this outer limit.

In addition, each housing unit may comprise a plurality of integrally molded resilient spring means for retaining core members and magnets therein. Core receiving fixtures may also be integrally molded with the housing unit to retain the cores in the proper position.

BRIEF DESCRIPTION OF THE DRAWINGS The specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention. The invention may also be understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a plan view of the front of the convergence apparatus as mounted on the neck of the cathode ray tube.

FIG. 2 is a plan view of the rear of the convergence apparatus as mounted on the neck of the cathode ray tube.

FIG. 3 is a plan view of the rear of the apparatus clamp.

FIG. 4 is a plan view of the edge of the apparatus clamp.

FIG. 5 is a perspective exploded view of one of the individual housing units or legs of the convergence apparatus with static and dynamic convergence means.

FIG. 6 is a plan view of one of the connective means on each of two housing units.

FIG. 7 is a perspective view of the elements of a magnetic flux path in a housing unit along with the dynamic convergence coils.

DESCRIPTION OF THE PREFERRED EMBODIMENT As disclosed in FIG. 1, the convergence apparatus is mounted on a neck 11 of a cathode ray tube with each of the individual housing units 12 circumferentially disposed around the neck 11. In order to achieve the proper convergence at a shadow mask (not shown) in the cathode ray tube, each of the housing units 12 is aligned with one of the electron guns (not shown) of the cathode ray tube projecting electron beams 13.

In order to aid in the retention of the housing units 12 on the neck of the cathode ray tube and to achieve the proper alignment of each housing unit 12 with the respective electron beam 13, connective means 14 are provided and terminate at one end of a clamp receiving, neck engaging portion 15. The connective means 14 comprises a male connective member 17 including parallel surfaces 16 which are radially spaced and tangentially extended with respect to the neck 11 of the cathode ray tube or the neck engaging portion 15. The male connective member 17 also includes stop means 18 which are partially shown through small apertures 19 in a cover member 52 of each of the housing units 12. Each of the male connective members 17 mates with a complementary female connective member 41 of an adjacent housing unit.

In addition to the aligning forces provided by the connective means 14, there is also provided a clamp 80 comprising guideways including parallel surfaces 81. These surfaces 81, which are substantially parallel to the radial projection bisecting each housing 12 and bear upon the sides 23, restrict displacement to the radial direction.

A portion of the magnetic structure itself may also be viewed in FIG. 1 wherein static convergence magnetic means are provided in the form of magnetic discs 21 which are mounted on those portions of the housing 12 which are radially remote from the neck engaging portions 15. Consistent with the objective of an integrally molded unit, placement of each disc 21 is effected by a resilient and integrally molded U-shaped flexible member 22 bridging each disc 21 from tangentially disposed sides 23. Support means for the circular magnet 21 are provided for at reinforced portions 24 in the bite of the U-shaped flexible members 22 by pivot projections 25; one of which is shown on the upper, outwardly radially flexed, member 22.

When viewing the convergence apparatus from the electron guns as shown' in FIG. 2, the magnetic cir cuitry and means of support therefore in each of the housing units 12 are more completely revealed. As may be seen, each unit 12 includes support members 30 with integrally molded support elements 31 providing a requisite overall strength to the unit. In addition, the support elements 31 along with the resilient fingers 32 provide a means of support for L-shaped cores 35 encircled with dynamic convergence coils 33 and 34. Furthermore, the tangentially directed forces provided by the resilient fingers 32 maintain the I.-shaped cores 35 in close proximity at juncture 36 in order to maintain a closed magnetic flux path. Immediately above the juncture 36, the flexible member 22 maintains the disc 21 in substantial contact with the L-shaped cores 35.

In order to allow radial displacement of the units 12, the clamp includes a plurality of slots 82 which permit the clamp to expand with the neck engaging portion 15. The dual function of the clamp 80 which permits expansion while maintaining alignment is more readily understood by reference to FIGS. 3 and 4. As shown there, additional bearing surfaces 83 have been provided which bear upon support members 30 to maintain the orthogonal relationship between the housing unit 12 and the cathode ray tube axis. In addition, clamping projections 84 have been provided which engage the neck engaging portion 15. i

The precise nature of the connective means 14 as comprising parallel surfaces 16 is more fully disclosed in FIG. 5 along with the radially projecting stop means 18 which form a T-shaped cross-sectional structure with a central aperture 40. The male connective member 17 mates with the female connective member 41 of an adjacent housing unit 12 identical to the connective member 41 shown as disposed at the opposite end of the neck engaging portion 15. The female connective member 41 also comprises radially spaced tangentially extending surfaces 42 which are terminated with radially extending projections providing stop means 43. In an assembled apparatus, the female connective member 41 receives the male connective member 17 in a sliding engagement allowing radial displacement of the individual housing units 12 along radially spaced and tangentially extending paths as provided by the parallel surfaces 16 and 42.

FIG. 5 also reveals the support member 30 of each housing unit 12 as possessing a depth along the sides 23 so as to accommodate the L-shaped core 35. In addition to the resilient fingers 32 which perform a retention function on the L-shaped cores 35, integrally molded receptacles 44 are provided in the neck engaging portion 15. Receptacles 44 serve to fix the position of the L-shaped core feet 45 to assure appropriate alignment with the proper electron beam 13. The receptacles 44 are then provided with axially extending apertures 46 in the neck engaging portions 15 for receiving pole shoes 47 which abut the feet 45 and are only slightly displaced from the neck 11. In order to retain pole shoes 47 and the L-shaped cores 35, a cover member 52, as shown in FIG. 5, is provided and secured to the support member 30 at integrally molded studs 53 which may be cold staked or heat deformed to secure the cover member 52in place.

The cover member 52 includes an integrally molded depression 54 which is centrally positioned and adapted to receive the elements of the magnetic flux path and provide overall depth to the housing 12 in excess of that provided by the sides 23. Additional depth is provided in the housing unit 12 by the thickness of the edge portions 55 surrounding the depressions 54, which edge portions 55 lie flush with the sides 23 when assembled and are secured thereto by insertion of the studs 53 through apertures 56. An extension 57 of the cover member 52 forms a closure member for each connective means 14 thereby retaining each male connective member 17 within each female connective member 41. In order to provide a better bearing surface on the neck ll, segments 70 of the neck engaging portion 15 extend normally from the edge portions 55, which segments 70 have a section of slots 46 therein.

As shown in FIG. 6, the male connective member 17 is maintained in an intermediate position within the female connective member 41. In the particular position disclosed, each of the housing units 12 will be radially displaced a lesser distance than the displacement required to accommodate the outer limit of the tolerances on the cathode ray tube neck 11. Such a displacement will result in movement along radially spaced and tangentially extending paths with respect to the neck of the cathode ray tube 11 due to the restriction of movement provided by the stop means 43 on parallel surfaces 16 and the'stop mean-s 18 on parallel surfaces 42.

The male connective members 17 and the female connective members 41 are thus able to assure that the elements of the magnetic flux path as illustrated in FIG. 7, namely the pole shoes 47, the coils 33 and 34, the L- shaped cores 35, and the circular magnets 21, are always maintained in the proper position. The coils are separated by an insulator 65 and wound on each of the L-shaped cores 35 around a support form 66. The circular magnet 21 is provided with an aperture 67 which allows it to be retained in the convergence housing units 12 by the projection 25 on the U-shaped flexible member 22.

Although a specific embodiment of the invention has been described and another suggested, it is not desired that the invention be limited to the particular form shown and it is intended by the appended claims to cover all modifications within the spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An electron beam convergence apparatus for use with a cathode ray tube including a neck traversed by a plurality of electron beams, said apparatus comprising; a plurality of housing units adapted to be circumferentially disposed around the neck, each of said housing units including a neck engaging portion, a pair of connective means individually disposed adjacent the ends of said neck engaging portion, each of said connective means of each of said housing units engaging one of said connective means of another of said housing units along at least two radially spaced and parallel paths tangential to the neck engaging portion, one of said connective means of one of said housing units including a first pair of radially spaced and tangentially extending surfaces and one of said connective means of another of said housing units including a second pair of radially spaced and tangentially extending surfaces, said first pair of surfaces mating internally with said second pair of surfaces to allow motion along two parallel paths tangential to the neck engaging portion and a flexible clamp bearing upon each of said housing units so as to restrict each of said housing units to substantially radial displacement, said first pair of surfaces having a first stop means associated therewith and said second pair of surfaces having a second stop means associated therewith, said first stop means and said second stop means engaging when said housing units are radially displaced.

2. The electron beam convergence apparatus of claim 5 wherein said first stop means and said second stop means comprise projections extending substantially radially from said first pair of surfaces and said second pair of surfaces respectively.

3. An electron beam convergence apparatus for use with a cathode ray tube including a neck traversed by a plurality of electron beams, said apparatus comprising: a plurality of housing units adapted to be circumferentially disposed around the neck, each of said housing units including a neck engaging portion, a pair of connective means individually disposed adjacent the ends of said neck engaging portion, each of said connective means of each of said housing units engaging one of said connective means of another of said housing units along at least two radially spaced and parallel paths tangential to the neck engaging portion, and a flexible clamp bearing upon each of said housing units so as to restrict each of said housing units to substantially radial displacement, each of said housing units comprising an integrally molded support member including said neck engaging portion and said connective means and further including integrally molded spring means.

4. The electron beam convergence apparatus of claim 3 wherein one of said connective means of one of said housing units includes a first pair of radially spaced and tangentially extending surfaces and one of said connective means of another said housing units includes a second pair of radially spaced and tangentially extending surfaces, said first pair of surfaces mating internally with said second pair of surfaces to allow motion along two parallel paths tangential to the neck engaging portion.

5. The electron beam convergence apparatus of claim 3 wherein said spring means includes a flexible member remote from said neck engaging portion and providing a radially directed force toward said neck engaging portion.

6. The electron beam convergence apparatus of claim 5 wherein said flexible member is U-shaped and forms a bridge tangential to said neck engaging portion.

7. The electron beam convergence apparatus of claim 6 wherein said spring means includes at least one resilient finger providing a force tangential to said neck engaging portion.

8. The electron convergence apparatus of claim 7 wherein said support member has a pair of receptacles adjacent said neck engaging portion with a pair of axially extending slots in said neck engaging portion positioned radially therefor inward from the receptacles.

9. The electron beam convergence apparatus of claim 8 wherein each of said housing units includes magnetic means with an aperture therein, a pair of L- shaped cores supported within the pair of receptacles with one of said cores abutting said one resilient finger, and said flexible member furtherincludes a radial projection extending toward said neck portion and inserted in the aperture.

10. The electron beam convergence apparatus of claim 9 wherein each of said housing units includes a cover member which is secured to said support member.

11. A convergence assembly adapted to be mounted on the neck of a multiple gun cathode ray tube, including a plurality of housing parts equal in number to the number of guns of the cathode ray tube, the inner end of each part terminating in a part cylindrical surface with a common radius of curvature, each of the parts carrying a convergence coil assembly for use in a dynamic convergence system for one of the guns of the cathode ray tube, each part having an elongated lock ing lug projecting from one side of the part cylindrical surface thereof with the longitudinal axis of the lug disposed approximately normal to the central axis of the part cylindrical segment of said part, each part having a complimentary locking chamber on the other side of the part cylindrical surface thereof, the locking lug of each part being disposed within and engaging the locking chamber of one of the other parts and restricting movement'of the lug to translation along the axis of elongation thereof, the parts thereby being mechanically interconnected to maintain the central axis of the part cylindrical surfaces parallel to each other to form a central opening between the parts, translation of the lugs within the chambers of the parts altering the size of the opening so the assembly can be mounted on cathode ray tube of different diameters, and locking means mechanically associated with each part for securing the parts in fixed positions in abutment with the neck of a cathode ray tube.

12. A convergence assembly for a cathode ray tube having three guns disposed about the axis of the neck of the tube and being equally spaced from each other comprising the combination of claim 11 wherein three housing parts are employed, each of the parts having a coil assembly producing a magnetic field in the central radial plane of the part cylindrical surface, and said radial planes being maintained at angles of approximately to each other.

13. A convergence assembly comprising the combination of claim 11 in which the locking means includes an arcuate wall section on each inner end of each part, said section extending normally to the plane of the central opening at the perimeter of the opening, and having a curved surface continuous with the part cylindrical surface and of the same curvature, an annular clamp engaging the sides of the arcuate sections opposite the opening and means to urge the annular clamp against the arcuate wall sections.

14. A convergence assembly comprising the combination of claim 13 wherein each arcuate wall section is provided with a tab extending outwardly from an edge of the arcuate wall section and spaced from the part thereof, and said tab slidably abutting one edgeof the ring to hold the ring between the tab and the part, said ring being removable from the arcuate sections by increasing the diameter of the ring. 

1. An electron beam convergence apparatus for use with a cathode ray tube including a neck traversed by a plurality of electron beams, said apparatus comprising; a plurality of housing units adapted to be circumferentially disposed around the neck, each of said housing units including a neck engaging portion, a pair of connective means individually disposed adjacent the ends of said neck engaging portion, each of said connective means of each of said housing units engaging one of said connective means of another of said housing units along at least two radially spaced and parallel paths tangential to the neck engaging portion, one of said connective means of one of said housing units including a first pair of radially spaced and tangentially extending surfaces and one of said connective means of another of said housing units including a second pair of radially spaced and tangentially extending surfaces, said first pair of surfaces mating internally with said second pair of surfaces to allow motion along two parallel paths tangential to the neck engaging portion and a flexible clamp bearing upon each of said housing units so as to restrict each of said housing units to substantially radial displacement, said first pair of surfaces having a first stop means associated therewith and said second pair of surfaces having a second stop means associated therewith, said first stop means and said second stop means engaging when said housing units are radially displaced.
 2. The electron beam convergence apparatus of claim 5 wherein said first stop means and said second stop means comprise projections extending substantially radially from said first pair of surfaces and said second pair of surfaces respectively.
 3. An electron beam convergence apparatus for use with a cathode ray tube including a neck traversed by a plurality of electron beams, said apparatus comprising: a plurality of housing units adapted to be circumferentially disposed around the neck, each of said housing units including a neck engaging portion, a pair of connective means individually disposed adjacent the ends of said neck engaging portion, each of said connective means of each of said housing units engaging one of said connective means of another of said housing units along at least two radially spaced and parallel paths tangential to the neck engaging portion, and a flexible clamp bearing upon each of said housing units so as to restrict each of said housing units to substantially radial displacement, each of said housing units comprising an integrally molded support member including said neck engaging portion and said connective means and further including integrally molded spring means.
 4. The electron beam convergence apparatus of claim 3 wherein one of said connective means of one of said housing units includes a first pair of radially spaced and tangentially extending surfaces and one of said connective means of another said housing units includes a second pair of radially spaced and tangentially extending surfaces, said first pair of surfaces mating internally with said second pair of surfaces to allow motion along two parallel paths tangential to the neck engaging portion.
 5. The electron beam convergence apparatus of claim 3 wherein said spring means includes a flexible member remote from said neck engaging portion and providing a radially directed force toward said neck engaging portion.
 6. The electron beam convergence apparatus of claim 5 wherein said flexible member is U-shaped and forms a bridge tangential to said neck engaging portion.
 7. The electron beam convergence apparatus of claim 6 wherein said spring means includes at least one resilient finger providing a force tangential to said neck engaging portion.
 8. The electron convergence apparatus of claim 7 wherein said support member has a pair of receptacles adjacent said neck engaging portion with a pair of axially extending slots in said neck engaging portion positioned radially therefor inward from the receptacles.
 9. The electron beam convergence apparatus of claim 8 wherein each of said housing units includes magnetic means with an aperture therein, a pair of L-shaped cores supported within the pair of receptacles with one of said cores abutting said one resilient finger, and said flexible member further includes a radial projection extending toward said neck portion and inserted in the aperture.
 10. The electron beam convergence apparatus of claim 9 wherein each of said housing units includes a cover member which is secured to said support member.
 11. A convergence assembly adapted to be mounted on the neck of a multiple gun cathode ray tube, including a plurality of housing parts equal in number to the number of guns of the cathode ray tube, the inner end of each part terminating in a part cylindrical surface with a common radius of curvature, each of the parts carrying a convergence coil assembly for use in a dynamic convergence system for one of the guns of the cathode ray tube, each part having an elongated locking lug projecting from one side of the part cylindrical surface thereof with the longitudinal axis of the lug disposed approximately normal to the central axis of the part cylindrical segment of said part, each part having a complimentary locking chamber on the other side of the part cylindrical surface thereof, the locking lug of each part being disposed within and engaging the locking chamber of one of the other parts and restricting movement of the lug to translation along the axis of elongation thereof, the parts thereby being mechanically interconnected to maintain the central axis of the part cylindrical surfaces parallel to each other to form a central opening between the parts, translation of the lugs within the chambers of the parts altering the size of the opening so the assembly can be mounted on cathode ray tube of different diameters, and locking means mechanically associated with each part for securing the parts in fixed positions in abutment with the neck of a cathode ray tube.
 12. A convergence assembly for a cathode ray tube having three guns disposed about the axis of the neck of the tube and being equally spaced from each other comprising the combination of claim 11 wherein three housing parts are employed, each of the parts having a coil assembly producing a magnetic field in the central radial plane of the part cylindrical surface, and said radial planes being maintained at angles of approximately 120* to each other.
 13. A convergence assembly comprising the combination of claim 11 in which the locking means includes an arcuate wall section on each inner end of each part, said section extending normally to the plane of the central opening at the perimeter of the opening, and having a curved surface continuous with the part cylindrical surface and of the same curvature, an annular clamp engaging the sides of the arcuate sections opposite the opening and means to urge the annular clamp against the arcuate wall sections.
 14. A convergence assembly comprising the combination of claim 13 wherein each arcuate wall section is provided with a tab extending outwardly from an edge of the arcuate wall section and spaced from the part thereof, and said tab slidably abutting one edge of the ring to hold the ring between the tab and the part, said ring being removable from the arcuate sections by increasing the diameter of the ring. 